/*
 * Copyright (c) 2007, 2015, Oracle and/or its affiliates. All rights reserved.
 * ORACLE PROPRIETARY/CONFIDENTIAL. Use is subject to license terms.
 */
/*
 * Copyright 1999-2004 The Apache Software Foundation.
 *
 * Licensed under the Apache License, Version 2.0 (the "License");
 * you may not use this file except in compliance with the License.
 * You may obtain a copy of the License at
 *
 *     http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 */
/*
 * $Id: StringComparable.java,v 1.2.4.1 2005/09/15 08:15:55 suresh_emailid Exp $
 */

package com.sun.org.apache.xml.internal.utils;

import java.util.Vector;
import java.text.Collator;
import java.text.RuleBasedCollator;
import java.text.CollationElementIterator;
import java.util.Locale;
import java.text.CollationKey;


/**
 * International friendly string comparison with case-order
 *
 * @author Igor Hersht, igorh@ca.ibm.com
 */
public class StringComparable implements Comparable {

  public final static int UNKNOWN_CASE = -1;
  public final static int UPPER_CASE = 1;
  public final static int LOWER_CASE = 2;

  private String m_text;
  private Locale m_locale;
  private RuleBasedCollator m_collator;
  private String m_caseOrder;
  private int m_mask = 0xFFFFFFFF;

  public StringComparable(final String text, final Locale locale, final Collator collator,
      final String caseOrder) {
    m_text = text;
    m_locale = locale;
    m_collator = (RuleBasedCollator) collator;
    m_caseOrder = caseOrder;
    m_mask = getMask(m_collator.getStrength());
  }

  public final static Comparable getComparator(final String text, final Locale locale,
      final Collator collator, final String caseOrder) {
    if ((caseOrder == null) || (caseOrder.length() == 0)) {// no case-order specified
      return ((RuleBasedCollator) collator).getCollationKey(text);
    } else {
      return new StringComparable(text, locale, collator, caseOrder);
    }
  }

  public final String toString() {
    return m_text;
  }

  public int compareTo(Object o) {
    final String pattern = ((StringComparable) o).toString();
    if (m_text.equals(pattern)) {//Code-point equals
      return 0;
    }
    final int savedStrength = m_collator.getStrength();
    int comp = 0;
    // Is there difference more significant than case-order?
    if (((savedStrength == Collator.PRIMARY) || (savedStrength == Collator.SECONDARY))) {
      comp = m_collator.compare(m_text, pattern);
    } else {// more than SECONDARY
      m_collator.setStrength(Collator.SECONDARY);
      comp = m_collator.compare(m_text, pattern);
      m_collator.setStrength(savedStrength);
    }
    if (comp != 0) {//Difference more significant than case-order
      return comp;
    }

    // No difference more significant than case-order.
    // Find case difference
    comp = getCaseDiff(m_text, pattern);
    if (comp != 0) {
      return comp;
    } else {// No case differences. Less significant difference could exist
      return m_collator.compare(m_text, pattern);
    }
  }


  private final int getCaseDiff(final String text, final String pattern) {
    final int savedStrength = m_collator.getStrength();
    final int savedDecomposition = m_collator.getDecomposition();
    m_collator.setStrength(Collator.TERTIARY);// not to ignore case
    m_collator.setDecomposition(Collator.CANONICAL_DECOMPOSITION);// corresponds NDF

    final int diff[] = getFirstCaseDiff(text, pattern, m_locale);
    m_collator.setStrength(savedStrength);// restore
    m_collator.setDecomposition(savedDecomposition); //restore
    if (diff != null) {
      if ((m_caseOrder).equals("upper-first")) {
        if (diff[0] == UPPER_CASE) {
          return -1;
        } else {
          return 1;
        }
      } else {// lower-first
        if (diff[0] == LOWER_CASE) {
          return -1;
        } else {
          return 1;
        }
      }
    } else {// No case differences
      return 0;
    }

  }


  private final int[] getFirstCaseDiff(final String text, final String pattern,
      final Locale locale) {

    final CollationElementIterator targIter = m_collator.getCollationElementIterator(text);
    final CollationElementIterator patIter = m_collator.getCollationElementIterator(pattern);
    int startTarg = -1;
    int endTarg = -1;
    int startPatt = -1;
    int endPatt = -1;
    final int done = getElement(CollationElementIterator.NULLORDER);
    int patternElement = 0, targetElement = 0;
    boolean getPattern = true, getTarget = true;

    while (true) {
      if (getPattern) {
        startPatt = patIter.getOffset();
        patternElement = getElement(patIter.next());
        endPatt = patIter.getOffset();
      }
      if ((getTarget)) {
        startTarg = targIter.getOffset();
        targetElement = getElement(targIter.next());
        endTarg = targIter.getOffset();
      }
      getTarget = getPattern = true;
      if ((patternElement == done) || (targetElement == done)) {
        return null;
      } else if (targetElement == 0) {
        getPattern = false;
      } else if (patternElement == 0) {
        getTarget = false;
      } else if (targetElement != patternElement) {// mismatch
        if ((startPatt < endPatt) && (startTarg < endTarg)) {
          final String subText = text.substring(startTarg, endTarg);
          final String subPatt = pattern.substring(startPatt, endPatt);
          final String subTextUp = subText.toUpperCase(locale);
          final String subPattUp = subPatt.toUpperCase(locale);
          if (m_collator.compare(subTextUp, subPattUp) != 0) { // not case diffference
            continue;
          }

          int diff[] = {UNKNOWN_CASE, UNKNOWN_CASE};
          if (m_collator.compare(subText, subTextUp) == 0) {
            diff[0] = UPPER_CASE;
          } else if (m_collator.compare(subText, subText.toLowerCase(locale)) == 0) {
            diff[0] = LOWER_CASE;
          }
          if (m_collator.compare(subPatt, subPattUp) == 0) {
            diff[1] = UPPER_CASE;
          } else if (m_collator.compare(subPatt, subPatt.toLowerCase(locale)) == 0) {
            diff[1] = LOWER_CASE;
          }

          if (((diff[0] == UPPER_CASE) && (diff[1] == LOWER_CASE)) ||
              ((diff[0] == LOWER_CASE) && (diff[1] == UPPER_CASE))) {
            return diff;
          } else {// not case diff
            continue;
          }
        } else {
          continue;
        }

      }
    }

  }


  // Return a mask for the part of the order we're interested in
  private static final int getMask(final int strength) {
    switch (strength) {
      case Collator.PRIMARY:
        return 0xFFFF0000;
      case Collator.SECONDARY:
        return 0xFFFFFF00;
      default:
        return 0xFFFFFFFF;
    }
  }

  //get collation element with given strength
  // from the element with max strength
  private final int getElement(int maxStrengthElement) {

    return (maxStrengthElement & m_mask);
  }

}//StringComparable
